https://github.com/meilisearch/heed

A fully typed LMDB wrapper with minimum overhead 🐦
https://github.com/meilisearch/heed

key-value-store lmdb memory-mapping typed wrapper

Last synced: 9 days ago
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A fully typed LMDB wrapper with minimum overhead 🐦

• Host: GitHub
• URL: https://github.com/meilisearch/heed
• Owner: meilisearch
• License: mit
• Created: 2019-10-04T16:25:17.000Z (over 5 years ago)
• Default Branch: main
• Last Pushed: 2024-11-16T15:20:37.000Z (6 months ago)
• Last Synced: 2024-11-16T16:27:01.415Z (6 months ago)
• Topics: key-value-store, lmdb, memory-mapping, typed, wrapper
• Language: Rust
• Homepage: https://docs.rs/heed
• Size: 3.25 MB
• Stars: 621
• Watchers: 16
• Forks: 55
• Open Issues: 36
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        


heed & heed3


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Rust-centric [LMDB](https://en.wikipedia.org/wiki/Lightning_Memory-Mapped_Database) abstractions with minimal overhead. These libraries enable the storage of various Rust types within LMDB, extending support to include Serde-compatible types. It supports not only the LMDB `mdb.master` branch but also the `mdb.master3` branch, which features encryption-at-rest.

## Simple Example Usage

Here is an example on how to store and read entries into LMDB in a safe and ACID way. For usage examples, see [examples/](examples/). To see more advanced usage techniques go check our [Cookbook](https://docs.rs/heed/latest/heed/cookbook/index.html).

```rust

use std::fs;

use std::path::Path;

use heed::{EnvOpenOptions, Database};

use heed::types::*;

fn main() -> Result<(), Box> {

    let env = unsafe { EnvOpenOptions::new().open("my-first-db")? };

    // We open the default unnamed database

    let mut wtxn = env.write_txn()?;

    let db: Database> = env.create_database(&mut wtxn, None)?;

    // We open a write transaction

    db.put(&mut wtxn, "seven", &7)?;

    db.put(&mut wtxn, "zero", &0)?;

    db.put(&mut wtxn, "five", &5)?;

    db.put(&mut wtxn, "three", &3)?;

    wtxn.commit()?;

    // We open a read transaction to check if those values are now available

    let mut rtxn = env.read_txn()?;

    let ret = db.get(&rtxn, "zero")?;

    assert_eq!(ret, Some(0));

    let ret = db.get(&rtxn, "five")?;

    assert_eq!(ret, Some(5));

    Ok(())

}

```

## Working with two Crates: heed and heed3

The heed and heed3 crates manage a shared codebase. Within the heed3 folder, you can find the Cargo.toml specific to the heed3 crate.

To facilitate work on heed3, utilize the `convert-to-heed3.sh` script.

This script conveniently moves the `heed3/Cargo.toml` file to the `heed/` folder, updates the `heed::` references to `heed3::`, and generates a commit for easy rollback if needed.

## Building from Source

You can use this command to clone the repository:

```bash

git clone --recursive https://github.com/meilisearch/heed.git

cd heed

cargo build

```

However, if you already cloned it and forgot to initialize the submodules, execute the following command:

```bash

git submodule update --init

```